1. Field of the Invention
The present invention relates to a radio access network system which divides functions of a control apparatus (a radio network controller) in a radio access network, so as to properly distribute loads and functions of the control apparatus, a radio communication method, a control server and a data server.
2. Description of the Related Art
In a conventional 3rd Generation Partnership Project (3GPP) specification, a control apparatus has both a user plane function of transferring user data and a control plane function of executing control in a radio access network.
The control plane function manages a configuration of a radio access network including a base station etc., and executes communication control such as signaling. The user plane function manages resources such as a port used on a transfer path during packet transmission/reception.
As shown in FIG. 1A, the control apparatus is located between a core network and a mobile station in a radio access network, according to the conventional 3GPP specification. As shown in FIG. 1B, the control apparatus executes the control plane function so as to set the transfer path for a packet, and executes the user plane function so as to carry out protocol conversion or packet transfer in accordance with a transmission path set by the control plane function.
However, in the conventional 3GPP specification, the control plane function and the user place function are located in the same control apparatus as described above, so that a load of processing performed by the control plane function and a load of processing performed by the user plane function in the radio access network are concentrated in the same control apparatus. As a result, for example, the processing performed by the control plane function or the processing performed by the user plane function can be delayed.
Moreover, when the radio access network is expanded, even if it is desired to reinforce only the user plane function, reinforcement must be made including the control plane function which needs no reinforcement. As a result, the expansion of the radio access network incurs unnecessary cost.